Oxidative stress is greater in patients with chronic heart failure due to coronary artery disease

Increased oxidative stress may play an important role in the pathophysiology of chronic heart failure (CHF). Coronary artery disease (CAD) is also associated with increased oxidative stress. In this study, we compared oxidative stress assessed by plasma lipid-derived free radicals in patients with CHF due to underlying CAD versus patients with CHF due to dilated cardiomyopathy (DCM). Methods: The study group consisted of 35 patients with NYHA class II-IV symptoms of CHF, LV ejection fractions <35% on optimal medical therapy, 25 of whom had underlying CAD, and 12 healthy controls. Lipid-derived free radicals from plasma samples were measured by electron paramagnetic resonance spectroscopy using the spin trap α-phenyl tert-butylnitrone with peak spectral heights recorded in arbitrary units(u). Results: (Data expressed as mean±SD) The CHF patients and controls were well matched for age and gender. The mean magnitude of EPR spectra obtained from the DCM group was significantly greater than controls (0.395±0.21u vs. 0.26± 0.12u,p<0.05). Plasma lipid-derived free radical levels were greater in the CHF patient group with underlying CAD than both the control group and those patients with DCM (0.534±0.29u vs. 0.26±0.12u,p<0.05 and vs. 0.395±0.21u,p<0.05 respectively). Conclusion: This study has demonstrated that free radical levels in venous blood are elevated in CHF patients regardless of the underlying aetiology. We have also shown that CHF patients with underlying CAD have higher levels of oxidative stress than those with DCM confirming the pro-oxidant nature of atherosclerosis. Further studies are now needed to establish the main source of free radicals in CHF, the pathophysiological mechanisms underlying this process and the potential therapeutic role of antioxidants.